This invention relates generally to energy cells or batteries of small size adapted for electric or electronic watches, hearing aids, cameras, paging systems and the like.
Small primary energy cells used, for example, in wristwatches and hearing aids are well known. These are generally of a circular configuration and known as "button" cells because of their shape. Such cells are generally inserted into or removed from the watch through an opening in the case back which is locked by a screw cover. The screw cover was heretofore needed to provide a dustproof and watertight closure of the watch case and for retaining under pressure the energy cell in electrical contact with the terminal portions of the watch. Typically, the screw cover formed one of the terminal portions and was, therefore, electrically connected to the watch circuitry. Examples of such cells and their use in electric watches and the like are illustrated in U.S. Pat. Nos. 3,916,613 issued Nov. 4, 1975 to Fred Esselborn; 3,708,343 issued Jan. 2, 1973 to Gerrard Walsh; 3,846,972 issued Nov. 12, 1974 to David Doss; 3,304,708 issued Feb. 21, 1967 to T. Baehni; and 3,670,491 issued June 20, 1972 to Milton E. Weschler. These prior art energy cells are undesirable, however, to the extent that they require a screw cover which both adds to the cost of manufacture of the wristwatch and the difficulty of replacing the battery by the user.
Accordingly, an object of the present invention is to provide an improved button cell configuration whereby the need for a screw cover is eliminated.
A further object of the present invention is to provide an improved button cell configuration which can be snapped-in and snapped-out of a watch or other device.
A still further object of the present invention is to provide an improved button cell configuration whereby electrical contact is established directly between a terminal of the button cell and the watch case without the need for a screw cover.
Another object of the present invention is to provide an improved button cell configuration which, when inserted into a wristwatch, provides a dustproof and watertight seal between the button cell and watch case.